LOS ANGELES, Aug. 12 (UPI) — Using hormone therapy for more than 15 years after menopause increases women’s risk of breast cancer, particularly leaner women, U.S. researchers say.
First author Dr. Tanmai Saxena of the Keck School of Medicine of the University of Southern California and colleagues did an analysis of the California Teachers Study, which focused on post-menopausal hormone therapy use among more than 55,000 women for nearly 10 years.
The study finds women who used estrogen therapy for more than 15 years were at a 19 percent increased risk of breast cancer and those who used combined hormone replacement therapy — estrogen plus progestin — for 15 or more years had an increased risk of 83 percent compared with women who never used post-menopausal hormone therapy.
Women with a body mass index of 30 or less appear to be at increased risk of breast cancer from combined therapy — estrogen plus progestin — while women who were heavier and had a BMI of 30 or higher were at less risk. Women with a BMI of 25 or less were at the highest risk, the study finds.
The 15-year Women’s Health Initiative was halted in 2002 after it appeared there was an increased risk of cardiovascular disease and breast cancer among women who were taking combination therapy.
The study is published in Cancer Epidemiology, Biomarkers and Prevention.
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